Atypical Sensory Alien Hand Syndrome: A Case Study

Case Report: Callosal disconnection syndrome manifesting as mixed frontal-callosal-posterior alien hand syndrome following extensive corpus callosum infarct

Alien hand syndrome (AHS) is a rare neurological phenomenon first described by Van Vleuten over a century ago. The most widely recognized variants in literature are frontal, callosal, and posterior AHS. AHS due to the corpus callosum lesion can occur alone or as part of callosal disconnection syndrome (CDS). This report presents a unique CDS case manifesting clinical features from all three AHS variants, resulting from an extensive corpus callosum infarct. Our patient exhibited various clinical features from the three AHS variants, which include grasping, groping, and difficulty releasing objects from the hand (anterior); intermanual conflict (callosal); arm levitation, mild hemiparesis, and hemisensory loss (posterior). Additionally, the extensive disruption of the corpus callosal fibers produced neurological manifestations of CDS, such as cognitive impairment, ideomotor and constructional apraxia, behavioral disorder, and transcortical motor aphasia. We employed a range of rehabilitation interventions, such as mirror box therapy, limb restraint strategy, verbal cue training, cognitive behavioral therapy, bimanual hand training, speech and language therapy, and pharmacological treatment with clonazepam. The patient showed almost complete resolution of CDS and AHS features by nine months post-stroke Our case report highlights distinctive clinical variations of AHS and the challenging correlation between clinical manifestations and neuroanatomical substrates. Future studies are necessary to explore the intricate neural connections and the precise function of the corpus callosum. This can be achieved by combining comprehensive neuropsychological testing with diffusion tensor tractography studies. It is also essential to develop a validated tool to standardize AHS assessment. Finally, the scarcity of evidence in rehabilitation interventions necessitates further studies to address the wide knowledge gap in AHS and CDS management.

Posterior Alien Hand Syndrome from Acute Ischemic Left Parietal Lobe Infarction

Alien hand syndrome (AHS) is defined as an involuntary goal-directed movement of the hand as if acting on its own will, or as being under the control of someone else. Moreover, the affected hand typically does not show any signs of weakness or convulsive movement. The cause of AHS is associated with an insult to the brain from various conditions such as stroke, trauma, tumor, aneurysm, neurosurgical intervention, infection, and degenerative brain diseases. We hereby illustrate a case of a patient with chronic atrial dysrhythmia whose oral anticoagulation therapy was placed on hold by his gastroenterologist for a scheduled colonoscopy. The patient presented to the hospital with symptoms of right-hand paresthesia with uncontrolled movement. These symptoms were seen along ST-segment elevation in the inferior leads on a 12 lead electrocardiogram. The case report acknowledges an unusual presentation of acute ischemic stroke, which may be frightening and bewildering to patients, their families, and any healthcare providers, including neurologists, who may have encountered it for the first time. Also, our patient had posterior AHS, likely from infarction involving the left inferior parietal lobe, which is reported to have a low prevalence.

Pathophysiology and treatment of alien hand syndrome

Background

Alien hand syndrome (AHS) is a disorder of involuntary, yet purposeful, hand movements that may be accompanied by agnosia, aphasia, weakness, or sensory loss. We herein review the most reported cases, current understanding of the pathophysiology, and treatments.

Methods

We performed a PubMed search in July of 2014 using the phrases “alien hand syndrome,” “alien hand syndrome pathophysiology,” “alien hand syndrome treatment,” and “anarchic hand syndrome.” The search yielded 141 papers (reviews, case reports, case series, and clinical studies), of which we reviewed 109. Non-English reports without English abstracts were excluded.

Results

Accumulating evidence indicates that there are three AHS variants: frontal, callosal, and posterior. Patients may demonstrate symptoms of multiple types; there is a lack of correlation between phenomenology and neuroimaging findings. Most pathologic and functional imaging studies suggest network disruption causing loss of inhibition as the likely cause. Successful interventions include botulinum toxin injections, clonazepam, visuospatial coaching techniques, distracting the affected hand, and cognitive behavioral therapy.

Discussion

The available literature suggests that overlap between AHS subtypes is common. The evidence for effective treatments remains anecdotal, and, given the rarity of AHS, the possibility of performing randomized, placebo-controlled trials seems unlikely. As with many other interventions for movement disorders, identifying the specific functional impairments caused by AHS may provide the best guidance towards individualized supportive care.

Controlling the alien hand through the mirror box. A single case study of alien hand syndrome

Disruption of motor control in the alien hand syndrome might result from a dissociation between intentions and sensory information. We hypothesized that voluntary motor control in this condition could improve by restoring the congruency between motor intentions and visual feedback. The present study shows that, in one patient with right alien hand syndrome, the use of a mirror box paradigm improved motor speed. We speculate that the visual feedback provided by the mirror increases the sense of congruence between intention and sensory feedback, leading to motor improvement.